Low blood pressure, or hypotension, occurs when blood pressure during and after each heartbeat is much lower than usual. When blood pressure is low, the heart is not pumping enough blood to perfuse the organs properly, which can lead to complications such as shock and injuries from a fall, according to the National Institutes of Health, or NIH.
Normal Blood Pressure
Blood pressure is recorded as two numbers. The top number, known as the systolic pressure, represents the pressure in the arteries as the heart contracts; the bottom number, known as the diastolic pressure, represents the pressure in the arteries when the heart relaxes. The National Institutes of Health explains that most blood pressures fall within the range of 90/60 to 130/80. Anything above 140/90 is commonly considered high blood pressure or hypertension and anything below 90/60 is often considered low blood pressure or hypotension.
Types
There are three main types of hypotension, according to NIH. The first type of hypotension, orthostatic hypotension, occurs due to a sudden change in position. Severe hypotension occurs due to sudden blood loss. Neurally mediated hypotension, the third type of hypotension, occurs in young adults and children when they have been standing for long periods.
Causes
Orthostatic hypotension often occurs when a person goes from sitting to standing or from lying to standing suddenly, according to the MayoClinic.com. This type of hypotension lasts often lasts only a few minutes, but can cause a loss of consciousness or fall. In some patients, this form of hypotension occurs after eating, known as postprandial orthostatic hypotension.
Neurally mediated hypotension, or NMH, occurs when a young adult or child has been standing for too long. Most people usually outgrow this form of hypotension. Certain medications may cause low blood pressure such as alcohol, anti-anxiety medications, antidepressants, diuretics, painkillers, heart medications and anesthesia medicines.
Warnings
Some conditions can cause potentially fatal low blood pressure. NIH warns that when a person experiences a severe allergic reaction, known as anaphylaxis, the body suffers an exaggerated histamine response that affects every system and can cause extremely low blood pressure. Low blood pressure can also occur due to cardiac conditions, such abnormal heart rhythms, heart attack and heart failure or from shock caused by severe infection, stroke or trauma.
Risk Factors
Low blood pressure can occur in anyone but is more common depending upon age and other factors. Orthostatic hypotension is more common in patients over 65 years of age. People who take medications for medications or heart related issues may experience low blood pressure especially after the age of 80, according to the MayoClinic.com. Patients with certain diseases are also more likely to develop low blood pressure, such as Parkinson's disease, diabetes and certain heart conditions.
